1. Field of the Invention
The present invention relates to electronic packaging and more specifically to bare die electronic packaging.
2. Description of the Related Art
Generally, integrated circuits are packaged using electronic packages with a lid (lidded) or without a lid (lidless or bare). In lidded electronic packaging, the lid serves as cover for the integrated circuit die to prevent structural damages and provides a mechanism to transfer force from the top of the electronic package to a circuit board on which the electronic package is installed. For bare or lidless electronic packages, the force transfer occurs through the integrated circuit die itself. The magnitude of force applied to the bare electronic package is typically smaller than the lidded electronic package to insure the structural integrity of the integrated circuit die.
Bare electronic packages have thermal advantage over lidded electronic packages. Eliminating the lid and thermal interface material from the lidded electronic package provides lower thermal resistance and better thermal performance for bare electronic package. Better thermal performance is critical for electronic packages with higher total power dissipation. Therefore, electronic circuits with high total power dissipation are typically packaged using bare electronic packaging. However, the amount of force that can be used on bare electronic packages is limited compared to the lidded electronic package. The limited force applicability can result in improper function such as, for example, the electronic package may not be properly inserted into a circuit board, or a cooling radiator may not establish proper conductive interface with the integrated circuit die resulting in poor thermal performance.
FIG. 1A illustrates an example of a typical use of a bare die electronic package with a cooling radiator. A circuit board assembly 100 includes a circuit board 110. A bare die electronic package with a substrate 120 and a bare die 130 is coupled to circuit board 110. Bare die 130 conductively interfaces with a cooling radiator 140 via a thermal interface material 150. Bare die 130 may not provide enough surface contacts for cooling radiator 140 for proper attachment. Thus, additional fastening mechanism is used for cooling radiator 140. Typically, cooling radiator 140 is further strengthened by two fastening bolts 170 and 175. However, other conventional means can be used to fasten cooling radiator 140. Often, bolts 170 and 175 cannot be fastened directly on circuit board 110 (e.g., due to the circuit layout, other electronic components, or the like) therefore, an additional bolster plate 160 is used to provide support for bolts 170 and 175.
The typical arrangement shown in FIG. 1A results in empty space 180 around bare die 130 under cooling radiator 140. Empty space 180 limits the amount of force that can be applied using bolts 170 and 175. Because empty space 180 does not provide guiding support underneath cooling radiator 140, applying additional fastening force on bolts 170 and 175 can result in the bending of cooling radiator 140 or it can cause structural damage to bare die 130. Empty space 180 around bare die 130 limits the amount of force that can be applied on bare die 130.
FIG. 1B illustrates the top view of circuit board 110 without cooling radiator 140. The surface area with thermal interface material 150 on bare die 130 is generally smaller compared to empty space 180 around bare die 130 on substrate 120. When a force is applied to bolts 170 and 175 to fasten cooling radiator 140 to bare die 130 then due to empty space 180 around bare die 130, the force is centered on bare die 130. To prevent the structural integrity of bare die 130, the amount of force that can be applied using bolts 170 and 175 is often significantly limited. The limited force can leave cooling radiator 140 without a proper conductive interface with bare die 130 and can cause poor thermal performance for bare die 130. Similarly, when cooling radiators are not needed for some bare electronic packages, the amount of force that can be applied to insert bare electronic packages into circuit boards can also be limited resulting in improper functioning of the integrated circuits. Therefore, a method and an apparatus are needed to allow parallel force transfer through a bare die electronic package.
In some embodiments, the present application describes a method and an apparatus for facilitating increased uniformity and diffusion of force transfer on a bare die electronic package for example, when such electronic package is attached to a circuit board. Additional force absorbent material is applied around a bare die in the bare die electronic package. The force applied to the bare die electronic package can be distributed to the additional force absorbent material. A curable force absorbent material is dispensed around the bare die in the bare die electronic package. The surface of the curable material is substantially parallel with the surface of bare die thus facilitating a substantially uniform force distribution through the bare die and curable material 0resulting in a robust bare die electronic package.
In an embodiment, a method in connection with electronic packaging is described. In some variations, the method includes dispensing a curable material, substantially covering an area around a die in a bare die electronic package, wherein a surface of the curable material is substantially parallel with a surface of the die. In some variation, the die is integral with a substrate. According to an embodiment, the bare die electronic package is installed on a circuit board. In an embodiment, the method includes curing the curable material. In some variation, the curable material substantially forms a frame around the die.
In an embodiment, an electronic package is described. According to an embodiment, the electronic package includes a die and a substrate integral with the die. In some variation, a curable material is dispensed substantially around the die and a surface of the curable material is substantially parallel with a surface of die. In some variation, the electronic package is a bare die electronic package. In some variation, the electronic package is installed on a circuit board. In some variation, the curable material forms a frame around the die on the substrate. In some variation, the frame substantially covers the substrate.